Although air travel is the safest way to travel in the world, aircrafts may overrun the runway in the process of taking off or landing due to operational errors, mechanical failure, bad weather and so on, causing serious accidents and accident proneness, which is one of the major threats to aviation safety. In recent years, with the continuous increase in flight volume, the occurrence of aircrafts overrunning the runway is also rising. Under such a situation that the overall accident rate in the civil aviation industry is steady with a little decrease, it has become a common task faced in the civil aviation industry about how to avoid serious accidents of crash and death after aircrafts overrunning the runway. Especially for some airports, it is difficult to build a runway end safety area that meets the requirements of length because of natural barriers (such as rivers and lakes, deep ditches, etc.), construction facilities, or other environmental factors limit outside the runway, or the construction cost is too high, or there is safety area that meets the minimum standards of ICAO (240 meters for airports of class 3 and 4) but the consequences are particularly serious in case of overrunning the end safe area. In response to these problems, the US has firstly developed the Engineered Material Arresting System (EMAS) as an alternative to the special airport that cannot be extended in the end safe area.
Engineered Material Arresting System (EMAS) is a crushable material with specific mechanical performance, which is, laid on the ground of the runway extension line in a thickness of tens of centimeters to form an arresting bed. Once an aircraft overruns the runway into the arresting bed, the crushable material is crushed under the rolling of the wheel, so as to absorb the kinetic energy of the aircraft, and to make the aircraft gradually slow down and eventually stop in the arresting bed under the premise that the aircraft and personnel safety is ensured. EMAS can provide the last reliable safety barrier for the aircraft overrunning the runway.
Therefore, the body material of the EMAS must have the following performances:
the body material has excellent waterproof ability;
the overall package of the arresting bed has excellent waterproofness;
the top cover (or cover plate) has excellent anti-ultraviolet and anti-aging ability;
having excellent weather resistance and being free from weather restrictions, namely, it can be used in wind, rain and snow;
safety to use: the entire system meets the requirements of flame retardance, fire resistance, non-toxic and environmental friendliness;
emergency rescue: having no hindrance to the passengers evacuation and emergency rescue vehicles closing to the aircraft;
design life: 20 years;
maintenance requirement: simple maintenance on a regular basis;
navigation and lighting facilities: no impact; and
the construction period: 60-80 days.
The cover plate of EMAS is made of a polyester material which has the problem of poor weather resistance and reflection. Poor weather resistance will lead to short service life; and reflection will interfere with the pilot's sight, causing flight accidents. Therefore, it is necessary to improve the mattness of the polyester cover plate. It is an efficient, economical and convenient measure to add a layer of matte special coating with good weather resistance to the surface of the polyester cover plate.
Single-component room-temperature cured silicone coating has excellent weather resistance, excellent resistance to high and low temperature and good water resistance. It can be long-term used in the range of −60˜200° C. Its theoretical service life is up to 20 years. There are no heat absorbing and heat release during curing, and the shrinkage percentage is small after curing; it has good adhesion to polyester materials and other good performance; and it is convenient to apply and easy to repair, greatly reducing the long-term maintenance costs. At the same time, it is non-toxic and environmentally friendly in itself. It has excellent mattness after being added with a certain matte material, and can be used for bonding, sealing, insulating, waterproof protection and other purposes. Therefore, its application to EMAS facilities will have huge social and economic benefits.